// Copyright (c) 2013 Stefan Penner and Ember App Kit Contributors

// MIT License

// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:

// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import Object from '@ember/object'
import { get } from '@ember/object';
import { computed } from '@ember/object';

export default function(groupBy) {
  var dependentKey = 'content.@each.' + groupBy;

  return computed(dependentKey, function(){
    var result = [];

    this.get('content').forEach(function(item){
      var hasGroup = !!result.findBy('group', get(item, groupBy));

      if (!hasGroup) {
        result.pushObject(Object.create({
          group: get(item, groupBy),
          content: []
        }));
      }

      result.findBy('group', get(item, groupBy)).get('content').pushObject(item);
    });

    return result;
  });
}